In a medium saucepan, combine chopped canned peaches, diced ripe mango, cornstarch, sugar, salt, and peach syrup. Cook over medium heat for about 3-5 minutes, stirring continuously until the mixture thickens and becomes bubbly. Once thickened, remove from heat and allow the filling to cool to room temperature.

On a lightly floured surface, roll out your thawed puff pastry sheet to smooth any creases. Cut the pastry into rectangles of about 4x6 inches.

Scoop a spoonful of cooled fruit filling into the center of each pastry rectangle. Fold the pastry over, enclosing the filling, and seal the edges tightly. Cut each filled pastry into separate pocket pies and freeze for at least 6 hours.

In a deep frying pan, heat about 2 inches of oil over medium heat until it reaches approximately 350°F (175°C). Fry the frozen pocket pies until they turn golden brown, usually around 3-5 minutes per side.

For baking, preheat your oven to 360°F (180°C), place the pastries on a baking sheet, and bake for 18-20 minutes until puffed and golden brown.